Method for producing prints in natural colors according to multicolor photography



Tatete d June 1,

NITED T TE A E DFFIe HANS EILOTY, OF MUNICH, GERMANY, ASSIGNOB TO THE FIRM OF JOB-PE FARBEN- PHOTO GESELLSGHAFT MIT BESCHRANKTER EAFTUNG, 0F HAMBURG, GERMANY.

:THOD FOR PRODUCING PRINTS IN NATURAL COLORS ACCORDING T0 MULTI- COLOR PHOTOGRAPHY.

Ho Drawing. Application tiled March 14, 1925, Serial No. 15,638, and'in Germany April 5, 1921.

p This invention refers to a method for preducing photographic multicolor pictures in which the color soluble in water is transmitted from gelatine reliefs produced from photographic silver pictures to paper, by the aid of a filmiof soft gela-tine by inhibition.

'by Couste and Dr. Franke. In contradistinction to the known processes this invention consists in. that hardening of the gelatine on the picture portions is eliected in 'de- 1 .veloping according to the method of Koppmann, German Patent 309193. This has the advantage that the gelatine silver picture layer comprising hardened portions to be deiveloped as relief is produced in the shortest possibleway, and'this means a saving of time'in the multicolor method; It is, how- 20 ever, not directly possible to make use 0f the Koppmann method for the multicolor print- -1ng.

For carrying out multicolor printing in the way explained, two classes of color or pigment will come into question, neither of which can be used directly, and therefore it is the object of the present invention to remove the difficulties inherent therewith.

The pigments or colors of the first class are those'which are adapted to color or tint the hard gelatine of the wash-relief, and which have been used in one-colorprinting with success. These colors have the peculiarity that they pass very quickly into the tint basis. Though this peculiarity is rawback for one-color printing, where under certain circumstances it is even desirable, in multicolor prints however it makes the adjustment of the part-printings im ossible. According to this inventionthis de ect is avoided by adding to the solution of the pigment a colloidal adhesive such as dextrin, gum-arabio and the like which reduces the speed of transmission of the color from the relief to the printing foundation. 1 The pigments of the second class are those which essentially color on tint only swollen up gelatine, and which also have beensuccessively used in multicolor printing by the aid of gelatine swelling reliefs (for instance .Methods of this kind have been proposed in pihatypie). These pigments, however,

acid, or the primary salts of the polybasic ac1ds.

It may happen that by the addition 0t acids, required for a sufficient coloring of the relief the rate of transmission of the pigment on to the base will be increased to too great an extent, so that-the color, in printing, will blot or blend, or a proper ad- ?)ustment of the partial prints will no longer e possible.

This defect is avoided according to the present invention, by giving the pigment solution besides the addition of the acid, an I addition of the above named colloidal adhesives, such as dextrin, in such a manner that the relief willbe suiiiciently colored, and also so that the pigment will not be transmitted too is taking place.

I claim:

1. A step in the method of producing prints in natural colors in multicolor photography b the aid of gelatine wash reliefs accor ing'to the known Koppmann method by the aid of known pigments, comprising, retarding the transmission of the pigment tothe paper by adding colloidal adhesives thereto.

2. A step in the method of producing prints in natural colors in multicolor photography by the aidv of gelatine wash reliefs according to the known Koppmann method b the aid of known pigments comprising a ding acid'to the pigment and also adding colloidal adhesives to the pigment.

NS PEOTY,

quickly while the printing- 

